<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>Document</title>
</head>

<body>
  <script>
    const str = 'abcd AB cd'
    const newStr = str.match(/[\w']+/g).map(item => item.split('').reverse().join('')).join(' ');
    // const newStr = str.split(/\s+/).map(s => s.split('').reverse().join('')).join(' ')
    console.log(newStr);

  </script>
</body>

</html>
